Pressure-regulated controlling device.



No. 767,138. PATENTED AUG. 9, 1904. A. S. COMSTOCK.

PRESSURE REGULATED GONTROLLING DEVICE. APPLIUATION FILED unl-1,1904.

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No. 767,138. PATENTED AUG. 9, 1904. A. S. GOMSTOCK.

PRESSURE REGULATED CONTROLLING DEVICE. APPLIOATION FILED APB.14, 1904.no MODEL. s snEnTs-snnnTzl PATENTED AUG. 9, 1904.

APPLICATION FILED APR.14., 1904.

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UNITED STATES ALPHONSO S. COINISTOCK,

Patented August 9, 1904.

OF EVANSTON, ILLINOIS.

PRESSURE-REGULATED CONTROLLING DEVICE.

SPECIFICATION forming part of Letters Patent No. 767,138, dated August9, 1904.

Application iiled April 14, 1904:.

To @ZZ whom it may concern:

Be it known that I, ALrHoNso S. CoMsTocK, a citizen of the UnitedStates, residing at Evanston, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements inPressure-Regulated Controlling' Devices, of which the following is aspecification.

My invention relates to improvements in .pressure-unloading devices,andl especially in apparatus for automatically unloading anaircompressor and for simultaneously shutting the power oif from thepump, and is particularly well adapted for use in connection withelectrically-operated air-compressors.

One object of my invention is to simultaneously unload the pump and shutthe power off from the motor.

Another object of my invention is to provide means for insuring therestarting of the pump at any desired diiference in pressure between thepoint at which the vapparatus blows off and the point at which it isdesired to restart the same.

Another object of my invention is to provide adjustable means forcontrolling the apparatus, so that when the pump is unloaded and a ventis provided to the atmosphere that vent shall be closed at any desiredpoint in the reduction of the pressure consequent upon the opening ofsuch vent.

These and such other objects as may hereinafter appear are attained bymy invention, which is typically embodied in the apparatus shown in theaccompanying drawings.

Like numerals of reference indicate the same parts in the severalfigures of the drawings, in which- Figure l is a longitudinal sectionalView of my apparatus in 'open position-1f. e., with the pump in freecommunication with the atmosphere and with the current shut off from themotor. Fig. 2 is a like view of the parts in reverse position-to wit,with the pump in operation and the vent to the atmosphere closed. Fig. 3is ahorizontal sectional detail on the line 3 3 of Fig. 2, looking inthe direction indicated by the arrows. Fig. i is an enlarged horizontalsectional detail on the line 4i l of Fig. 2, looking in the directionindi- Serial No. 203,173. (No model.)

cated by the arrows; and Fig. 5 is a representation of anelectrically-driven air-pump connectedV with an air-tank and fitted withmy improved apparatus.

Referring by number to the accompanying drawings, and especially to Fig.5, l indicates an air-compressor of any familiar type provided with afly-wheel 2 and driven by a motor 3. The wires conveying' power to themotor 3 are connected with a switch t, which in the drawings is shown asa two-point doublebreak switch, but which may be a switch of anyconvenient or desired form.

Leading from the air-compressor l to the tank 5 is a main 6, providedwith a lcheckvalve 7 and with a hand-operated drip-cock 8. Connectedwith the main 6 by a T 9 is an outlet-pipe lO. rI`he T 9 is preferablyarranged between the pumpl and the check-valve 7. The pipe 10communicates with a valve-CaS- ing 1l, which is divided into avalve-chamber l2 and an outlet-chamber 13 by a partition 14., whichaffords a seat for the valve l5. The valve l5 is normally held to itsseat by yielding means-such, for example, as the spring 16v which can beconveniently mounted within the plug I7, which closes one end of thevalve-chamber 1Q.

Extending through the outlet-chamber 13 is a stem 18, which abuts at oneend against the valve l5 and is provided with a broad bearing at itsopposite end against a iexible diaphragm 19, mounted within adiaphragmcasing 20. rlhe stem 18 is provided with a pin 2l, whichextends upwardly through a slot 9.2, opening from the outlet-chamber I3.

The casing 1l carries upon its upper surface standards 23, which supporta pivot 24, upon `which is journaled the stem 25, which carries a bridge26 of the switch 4.. rIhe lower end of the stem 25 is provided with anotch 27, arranged to engage the pin or tooth 2l upon the stem I8. Thebridge 26 is arranged to make contact with and be clamped between theusual spring-terminals 28 29, which are provided, respectively, with thebinding-posts 30 3l. rI`he wires or mains from the dynamo are connectedwith the binding-posts 3l, and the wires leading to the motor areconnected with the binding-posts 30. Connected with the main IOO 6 andpreferably between the check-valve 7 and the tank is a second T 32, fromwhich connections 33 lead to a valve-casing 34. This casing 34 isdivided by a partition 35 into an outer chamber 36 and a valve-chamber37, connecting with each other through a small port 38. The port 38 isnormally closed bya double-acting Valve 39, which is mounted within thevalve-chamber37. The lower end of the valve 39 is arranged to close theport 38, while the upper valve-face 4l of the valve 39 is adapted toclose the passage leading from the valve-chamber 37 to the atmosphere. Ihave found that in order to obtain the most satisfactory and reliableresults the area of the valve end 40 should be much smaller than thearea of the valve-face 41. The valve 39 is so proportioned that when thevalve-face 40is seated to close the port 38 the valve-facev4l will beunseated and there will be a free opening from the valve-chamber 37 tothe atmosphere. On the other hand, when the valve-face 40 is unseatedfrom the port 38 the valve-face 41 will be seated, so that the openingfrom the valve-chamber 37 to the atmosphere will be closed while thevalve-chamber 37 will be in free communication through the connection 33and the T 32 with the pressure in the main 6.

The upper portion 4l of the valve 39 is preferably formed so as toconstitute a guide for the travel of the valve within the passageleading from the valve-chamber 37 to the atmosphere. This portion 42 ofthe valve is cut away, as shown in detail in the cross-sectional viewshown in Fig. 4, so as to allow a free passage of air through thepassage leading from the valve-chamber 37 to the atmosphere and past theportion 42 of the valve 39. The valve 39 is also provided with aprojecting valve-stem 43. The valve 39 is normally held in positionwhere the valve-face 40 closes the port 38 bythe tension of a spring 44,which surrounds the valve-stem 43 and abuts against the 4shoulder formedwhere the valve enlarges from the valve-stem 43 to the' larger portion42. The valve-stem 43' projects longitudinally through and outside of ahollow plug 45, within which is mounted the spring 44. This plug' 45y'is screw-threaded into the Lipper end ofthe casing 34 and serves toadjust the tensionof the spring 44.

Since the port 38 will be opened by Huidpressure within the connection33 when such pressure against the valve-face 40 is sufcient to overcomethe tension of the spring 44, it will be understood that the pressure atwhich the port 38 will be opened will be determined by the adjustment ofthe adjusting-plug 45. It is well known, however, that with all blow-offvalves the valve will reseat only after a large reduction in thepressure, so Vthat while a valve may be blown off at a pressure ofthirty pounds the pressure mustA fall far below thirty pounds with asimple blow-0E valve before the valve will be reseated. This of coursewill result in a very objectionable reduction in pressure where it isdesired to maintain the pressure at approximately the point at which thevalve blows o or at a minimum pressure of a definite amount below thepoint at which the valve is set to blow olf.

To insure the reclosing of the valve 39, so as to close the port 38 atany desired reduction in pressure below the point at which the valve isset to blow off, I provide supplemental mechanism, as follows: 46 is adiaphragmcasing communicating by means of a pipe 47 with a casing 48. Toinsure the gradual action of the apparatus, the inlet to the pressureside of the diaphragm-casing 46 should be of restricted area, or thepassage through the connection 47 may be restricted, as at 49,'in anyconvenient manner. Although as a convenient means of supporting thediaphragm-casing 46 and connected parts I connect the casing 48 with thecasing 33 by means of a plug 50, it should be understood that there isno direct communication between the casing 3 3 and the casing 48, butthat the plug 50 is merely an imperforate connection or aV piece Bymeans of a by-pass or shunt-pipe 5l I establish communication betweenthe connecting-pipe lO and the casing 48, so that the casing 48 will atall times be subjected to pumppressure and likewise the pressure side ofthe diaphragm-casing 46 will be subjected to pump-pressure, although byreason of the restricted passage at 49 there will be an appreciable timein adjusting the conditions within the pressure side of the casing 46 tothe variations of pump-pressure.

Clamped across the diaphragm-casing 46, so as to divide it into apressure-chamber 53 and an atmospheric chamber 54, is a flexiblediaphragm 52. Resting upon the diaphragm 52 is a stem 53, which projectsthrough the diaphragm-casing 46.

54 is a pivoted lever which is preferably mounted, as shown-to wit,pivoted at one end to a suitable lug 55 formed upon the casing 46. Thefree end of the lever 54 is adapted to rest upon the upper end of thevalve-stem 43 with a yielding pressure, which may be varied at will bymeans of a thumb-nut 56. This nut 56 is screwed upon a stem 57, whichextends through the lever-arm 54. Secured to the opposite end of thestem 57 is a spring' 58, which is anchored at 59 to a rigid part of thestructure. By means of the thumb-nut 56 the tension .of the spring 58 isso adjusted that the pressure within the diaphragm pressure-chamber 53will operate the diaphragm 52 and lift the lever 54 out of Contact withthe valvestem 43 before the pressure within the connection 33 will causethevvalve 39 to unseat from the port 38.

Consequently the operation of my device is as follows: Assuming that thespring 58' has IOO been so adjusted that its tension will be overcome bya pressure oftwenty-eight pounds within the air-pressure pipe andassuming' that the spring 44 has been adjusted so that its resistancewill be overcome by a pressure of thirty pounds within the pipes andagainst the valve-face 49, the operation of my apparatus will be asfollows: Startingwith the parts in the position shown in Figs. 2 and 5,the motor will start the pump into operation and the pump will cause aflow of compressed air through main 6, past check-valve 7, and into thetank. lV hen the pressure within the pipe 51 reaches twenty-eight poundsor shortly thereafter, the pressure within the chamber 53 of thediaphragm-casing will reach twentyeight pounds and will raise theflexible diaphragm 52, carrying with it the stem 53L and the lever 54,against the tension of the spring 58, thereby carrying the lever 54'outof contact with the valve-stem 43. Now as the pressure continues toincrease it will reach thirty pounds within the tank and will unseat thevalve-face 40 from the port 38, and immediately the inrush of air to theport 38 and against the enlarged under surface Of the valve-face 41 willforce the valve-face 41 to close the passage leading from thevalve-chamber 37 to the atmosphere. in the pipes will then have freeaccess to the pressure-chamber of the diaphragm-casing 2O and willexpand the diaphragm 19, carrying with it the stem 18, against the valve15 and the resistance of the spring 16. This will simultaneously unseatthe valve 15 from the port connecting the valve-chamber 12 with theoutlet-chamber 13, thus affording a free vent from the pump to theatmosphere, and will carry the pin 21 upon the stem 18 laterally towardthe switch 4, thereby swinging the stem 25 upon the pivot 24 in adirection to carry the bridge 26 out of engagement with thespring-terminals 28 '29, thereby causing a double break in the circuitand shutting off the power from the pump. I thus have the motive forceshut off from the pump, and as the pump gradually comes to a standstillit will pump to the atmosphere through the main 6, T 9, pipe 10,valve-chamber 12, and outletchamber 13, as indicated by the arrows in Fig. 1. The check-valve 7, however, prevents any loss of pressure fromthe tank backward through said outlet, and therefore so long as Thepressure withreduces the pressure to below twenty-eight pounds, because,as is well known, although the valve 39 will be originally lifted fromthe port 38 by thirty-pounds pressure it will not return to its seatunaided until the pressure has dropped far below thirty pounds. lith mydevice, however, when the tank-pressure drops below twenty-eight poundsthe tension of the spring 58 will overcome the pressure exerted in thepressure-chamber 53 against the diaphragm 52, and will thus draw the arm54 downwardly. The arm 54 being in contact with the valve-stem 43 thetension of the spring 58 will serve to supplement the expansive force ofthe spring' 44, and the valve 39 will thus be promptly closed againstthe port 38 as soon as the tank-pressure drops below twenty-eight poundsor such other pressure for which the spring 58 has been adjusted bymeans of the thumb-nut 56 and threaded stem 57. As soon as theValve-face 40 of the valve 39 is seated to close the ports 38 allcommunication between the pressure-chamber 60 of the diaphragm-casing 2Oand the pump or the tank is shut off, while at the same time theunseating of the valve-face 41 from the port leading from thevalve-chamber 37 to the atmosphere will leave a free vent from thevalvechamber 60, past the flattened sides of the portion 42 of the valve39, and through the cap 45. The flexible diaphragm 19 being thusrelieved from pressure from the chamber 60 the spring 16 will seat theValve 15, thus closing the vent from the pump to the atmosphere, andwill also force the stem 18 to its original position, carrying with itthe pin 21, which gives a reverse swing to the stem 25, snaps thebridges 26 into contact with the springterminals 28 and 29, therebyclosing the circuit, switching on the power, and starting the pump. Asthe pump starts there is an entire freedom from pressure within thepipes between the pump and the check-valve 7 and between the pump andthe valve 15, so that the pump is started and the fly-wheel acquiresmomentum before any perceptible load, due to the compression of the airwithin the pipes, is put upon the mechanism. This not only makes morecertain andprompt the starting of the mechanism, but where, asillustrated, an electric motor is used it makes it practical to use ahigh-power motor with mechanism of this sort upon a power-circuit whichis common to a plurality of motors, where otherwise such an arrangementis commonly forbidden by the authorities and by the power companies forthe reason that with this embodiment of myv invention the momentum whichis acquired by the apparatus before encountering any substantial loadenables the apparatus to be started without any great increase of powerover the normal power required to run the mechanism, and there istherefore no sudden and great lowering of thc voltage of the circuit,due to the sudden ex- IOO IlO

ism is interposed in a circuit common to a plurality of devices theinstallation of a starting-box is insisted upon for the reasonexplained; but with my apparatus no startingbox is needed, because theincrease of power required when starting the mechanism is so slight asto be entirely free from objections of this nature.

From the foregoing explanation it will be seen that the diaphragm 19 andits associated parts constitutes a pressure-motor arranged to open thevalve l5 and the diaphragm 52 and its associated parts constitutes apressure-motor arranged to lift the lever-arm 54. For convenience I havetherefore used the term pressure-motor in the claims as indicating thesestructures, which serve to open the valve 15 and to lift the lever-arm54, respectively, under suitable conditions. Of course the exact form ofpressure-motor shown is merely illustrative and equivalent forms maybesubstituted therefor.

It will be understood that I have shown and explained my device'in itspreferred form and that various alterations in detail may be made as amatter of shop convenience or mere mechanical skill without departingfrom the spirit of my invention, which contemplates all such changes.

While I have especially designed my apparatus for use in connection withair-compressing machinery, it will be readily understood that it has awider field of usefulness and is adapted for use wherever it is desiredto unload pressure at a predetermined point and to have the exhaust-portagain closed after a slight reduction in pressure. So, also, my devicewill work equally well as an unloading device where the pump is drivenby other than electrical power and may be manufactured for such purposewithout the electric switch.

I claim- 1. The combination with a source of pressure, of apressure-motor, means connecting the pressure-motor with said source ofpressure, a valve arranged to normally shut off pressure from said motorand to be opened by a given pressure to admit pressure to said motor,supplemental means for holding said valve in a position to shutoffpressure from said motor. a second pressure-motor arranged to beoperated by a lower pressure than that required to open said valve, saidsecond motor being arranged 1.o operate under pressure to relieve saidvalve from the action of said supplemental means, and connectionsbetween the source of pressure and said second pressuremotor.

2. The combination with a pump, of a tank, a conduit connecting the pumpwith the tank, a vent leading from the pump to the atmosphere, aspring-pressed valve arranged to close said vent, a pressure-motorarranged to be actuated by tank-pressure to open said valve, a secondvalve arranged to alternately shut off tank-pressure from said motor andopen a vent from said motor to the atmosphere, and vice versa, a springarrangedto normally hold said valve in position to exclude tank-pressurefrom said motor, a second spring arranged to also hold said valvenormally so closed, a second pressure-motor arranged to communicate'with pump-pressure, and means interposed between said second motor andsaid second spring, all soy arranged that said second motor will beoperated against the energy of said second spring to relieve saidlast-named valve from the action of said spring before said valve willbe unseated by tank-pressure.

3. The combination with a pump and a tank, of a conduit connecting thesame, apressuremotor, a valve arranged to normally shut o pressure fromsaid motor and to be actuated by a predetermined pressure to admitpressure to said motor, supplemental means for normally holding saidvalve in a position to shut off pressure from said motor, and a secondpressure-motor arranged to be operated by a lower pressure than thatrequired to vopen said valve, said second motor being so arranged that,when actuated by pressure, it will relieve said valve from the action ofsaid supplemental means.

4. The combination with a pump, of a pressure motor communicatingtherewith and adapted to be operated by pump-pressure, a valve arrangedto normally close communication between the pump and said pressure-motorand to be actuated by a given pressure so as to admit pump-pressure tosaid motor, means for returning said valve to said normal position, andsupplemental means for returning said valve to said normal position, anda second motor in communication with pumppressure and arranged to beactuated by a lower pressure than that required to unseat said valvefrom its normal position, said second motor being so arranged that, whenactuated by pump-pressure, it will relieve said valve from the action ofsaid supplemental means.

5. The combination with an air-compressor, of an electric motor arrangedto drive said compressor, an electric circuit arranged to convey anelectrical current to said motor, a switch interposed in said circuit, apressuremotor communicating with said compressor and arranged to beactuated by pump-pressure, means arranged to be actuated by theoperation of said pressure-motor to open and close said switch, a valvefor normally excluding pump-pressure from said pressuremotor, said valvebeing arranged to be opened by pump-pressure, means for returning saidvalve to its closed position, supplemental means for returning saidvalve to its closed position, a second pressure-motor in communicationwith said pump and arranged to be IOO aetuated by a lower pressure thanthat required to unseat said Valve from its normal position andarranged, when so actuated, to operate said supplemental valve-closingmeans, so as to relieve said Valve from the action of said supplementalmeans.

6. The combination with an air-compressor, of a casing in freecommunication therewith, an outlet leading from the interior of saidcasing to the atmosphere, a Valve yieldingly seated to close saidoutlet, a motor-casing, a pressure-motor mounted within said casing,means interposed between said pressure-motor and said valve, wherebysaid valve may be unseated by the operation of said motor, a tank, aconduit connecting the pump with the tank, acheck-valve interposed insaid conduit, a valve-casing communicating with the pressure side of themotor-casing and provided with a port arranged to admit tankpressure andwith asecond port communicating with the atmosphere, a valve arrangedwithin said casing to alternately Close said ports and normally held byspring-pressure so as to close communication between said Valve-casingand the tank, a spring arranged to hold said valve so seated, a secondspring, means, interposed between said second spring and said valve,whereby said second spring also serves to hold saidvalve so seated, asecond motor-casing,means for Conducting pumppressure to said secondmotor-casing, a pressure-motor mounted in said casing, and meansinterposed between said motor and said lastnamed spring so that saidmotor will operate against the tension of said last-named spring torelieve said Valve from the action of said spring, substantially asdescribed.

ALPHONSO S. COMSTOCK. Witnesses:

O. R. BARNETT, M. E. SHIELDs.

